package licensing

import (
	"crypto/sha256"
	"encoding/hex"
	"strings"

	"github.com/rcourtman/pulse-go-rewrite/internal/models"
	agentsdocker "github.com/rcourtman/pulse-go-rewrite/pkg/agents/docker"
	agentshost "github.com/rcourtman/pulse-go-rewrite/pkg/agents/host"
	agentsk8s "github.com/rcourtman/pulse-go-rewrite/pkg/agents/kubernetes"
)

// MaxMonitoredSystemsLicenseGateKey is retained only to identify and scrub
// retired v5/v6 monitored-system volume-limit metadata from old licenses,
// billing records, purchase-return state, and entitlement leases.
const MaxMonitoredSystemsLicenseGateKey = "max_monitored_systems"

// InstalledUnifiedAgentCount returns the number of installed Pulse Unified
// Agents. This is inventory-only metadata and is not a commercial counted unit.
func InstalledUnifiedAgentCount(state models.StateSnapshot) int {
	return len(state.Hosts)
}

func CanonicalizeMonitoredSystemLimitKey(key string) string {
	normalized := strings.TrimSpace(key)
	switch normalized {
	case "", MaxMonitoredSystemsLicenseGateKey:
		return MaxMonitoredSystemsLicenseGateKey
	}
	if canonical, ok := canonicalizeLegacyV5MonitoredSystemLimitKey(normalized); ok {
		return canonical
	}
	return normalized
}

func NormalizeMonitoredSystemLimits(limits map[string]int64) map[string]int64 {
	if limits == nil {
		return nil
	}
	normalized := cloneInt64Map(limits)
	delete(normalized, MaxMonitoredSystemsLicenseGateKey)
	for _, key := range legacyV5MonitoredSystemLimitAliasKeys {
		delete(normalized, key)
	}
	return normalized
}

func HostReportTargetsExistingHost(
	snapshot models.StateSnapshot,
	report agentshost.Report,
	tokenID string,
) bool {
	return HostReportTargetsExistingHosts(snapshot.Hosts, report, tokenID)
}

func HostReportTargetsExistingHosts(
	hosts []models.Host,
	report agentshost.Report,
	tokenID string,
) bool {
	hostname := strings.TrimSpace(report.Host.Hostname)
	tokenID = strings.TrimSpace(tokenID)

	candidates := CollectNonEmptyStrings(
		report.Host.ID,
		report.Host.MachineID,
		report.Agent.ID,
	)

	for _, existing := range hosts {
		for _, candidate := range candidates {
			if existing.ID == candidate || existing.MachineID == candidate {
				return true
			}
		}

		if hostname != "" && strings.EqualFold(existing.Hostname, hostname) {
			// Token-bound identity takes precedence when token is present.
			if tokenID == "" || (existing.TokenID != "" && existing.TokenID == tokenID) {
				return true
			}
		}
	}

	return false
}

func DockerReportTargetsExistingHost(snapshot models.StateSnapshot, report agentsdocker.Report, tokenID string) bool {
	hostname := strings.TrimSpace(report.Host.Hostname)
	agentKey := strings.TrimSpace(report.AgentKey())
	tokenID = strings.TrimSpace(tokenID)

	for _, existing := range snapshot.DockerHosts {
		if agentKey != "" && (existing.ID == agentKey || existing.AgentID == agentKey || existing.MachineID == agentKey) {
			return true
		}

		if hostname != "" && strings.EqualFold(existing.Hostname, hostname) {
			if tokenID == "" || (existing.TokenID != "" && existing.TokenID == tokenID) {
				return true
			}
		}
	}

	return false
}

func KubernetesReportTargetsExistingCluster(snapshot models.StateSnapshot, report agentsk8s.Report, tokenID string) bool {
	identifier := KubernetesReportIdentifier(report)
	agentID := strings.TrimSpace(report.Agent.ID)
	clusterName := strings.TrimSpace(report.Cluster.Name)
	tokenID = strings.TrimSpace(tokenID)

	for _, existing := range snapshot.KubernetesClusters {
		if identifier != "" && existing.ID == identifier {
			return true
		}
		if agentID != "" && existing.AgentID == agentID {
			return true
		}

		if tokenID != "" && existing.TokenID == tokenID {
			if identifier == "" || existing.ID == identifier {
				return true
			}
			if clusterName != "" && strings.EqualFold(existing.Name, clusterName) {
				return true
			}
		}

		if tokenID == "" && identifier == "" && clusterName != "" && strings.EqualFold(existing.Name, clusterName) {
			return true
		}
	}

	return false
}

func KubernetesReportIdentifier(report agentsk8s.Report) string {
	if v := strings.TrimSpace(report.Cluster.ID); v != "" {
		return v
	}
	if v := strings.TrimSpace(report.Agent.ID); v != "" {
		return v
	}
	stableKey := strings.TrimSpace(report.Cluster.Server) + "|" + strings.TrimSpace(report.Cluster.Context) + "|" + strings.TrimSpace(report.Cluster.Name)
	stableKey = strings.TrimSpace(stableKey)
	if stableKey == "||" || stableKey == "" {
		return ""
	}
	sum := sha256.Sum256([]byte(stableKey))
	return hex.EncodeToString(sum[:])
}

func CollectNonEmptyStrings(values ...string) []string {
	out := make([]string, 0, len(values))
	seen := make(map[string]struct{}, len(values))
	for _, value := range values {
		trimmed := strings.TrimSpace(value)
		if trimmed == "" {
			continue
		}
		if _, exists := seen[trimmed]; exists {
			continue
		}
		seen[trimmed] = struct{}{}
		out = append(out, trimmed)
	}
	return out
}